class_docstr: Simple trajectory data writer. Serializes trajectory data for each episode
  into a separate file using Pickle.
  
  Suitable for smaller scale rollouts or debugging.
  
  :param log_dir: Where trajectory data should be logged.
code: def __init__(
      self, log_dir: Union[str, Path] = Path("./trajectory_data")
  ):
      self.log_dir = Path(log_dir)
      self.log_dir.mkdir(parents=True, exist_ok=True)
  
file_path: maze/maze/core/trajectory_recording/writers/trajectory_writer_file.py
imports: import pickle
  from pathlib import Path
  from typing import Union
  from maze.core.annotations import override
  from maze.core.trajectory_recording.records.trajectory_record import StateTrajectoryRecord
  from maze.core.trajectory_recording.writers.trajectory_writer import TrajectoryWriter
label_desc: Use image node_id 1 to create a new TrajectoryWriterFile object from inherited base classes: TrajectoryWriter with example: obj = TrajectoryWriterFile(log_dir)